Flange coupling and manufacturing method for the same

ABSTRACT

An object of the present invention is to provide a flange coupling in which the height of a horizontal portion of an L-shaped pipe is made as small as possible. The present invention provides a flange coupling having a flange formed with an attaching bolt hole and a pipe connection hole and an L-shaped pipe installed in the pipe connection hole, wherein the L-shaped pipe is made of aluminum or aluminum alloy, and a horizontal portion of the L-shaped pipe is molded so that a lower face thereof is at the same level as or at the level close to a plane including the upper surface of the flange.

TECHNICAL FIELD

The present invention relates to a flange coupling and, moreparticularly, a flange coupling used for automotive air conditionerpiping, and a manufacturing method for the same.

BACKGROUND ART

There has been conventionally available a flange coupling in which apipe 4 is welded to the side face of a flange 3, for example, as shownin FIG. 1. However, the coupling of this type has a drawback ofrequiring a welding process. Therefore, there can be used a flangecoupling in which an L-shaped pipe 4 is installed to the flange 3 and ahorizontal portion 5 of the pipe 4 is extended transversely with respectto the flange 3 as shown in FIG. 2.

However, for the flange coupling shown in FIG. 2, the radius of a bentportion must be made inevitably large because of the hardness of pipeused normally, so that the horizontal portion 5 of the pipe 4 has aconsiderably great height h with respect to the flange 3. Therefore, theflange coupling of this type is unsuitable in the case where it isarranged in an extremely limited space near an engine.

DISCLOSURE OF THE INVENTION

An object of the present invention is to make the height h of ahorizontal portion of an L-shaped pipe nearly zero to solve the aboveproblem.

To achieve the above object, the present invention provides a flangecoupling having a flange formed with an attaching bolt hole and a pipeconnection hole and an L-shaped pipe installed in the pipe connectionhole, wherein the L-shaped pipe is made of pure aluminum or aluminumalloy having soft properties or aluminum having elongating propertiesthough being hard, and a horizontal portion of the L-shaped pipe ismolded so that a lower face thereof is at the same level as or at thelevel close to a plane including the upper surface of the flange.

Also, the present invention provides a manufacturing method for a flangecoupling, comprising the steps of bending a pipe made of pure aluminumor aluminum alloy having soft properties or aluminum having elongatingproperties though being hard into an L shape with a radius of curvaturethat satisfies the condition of R≦1.0D (R: radius, D: pipe diameter);placing the L-shaped pipe in a pipe clamp mold and correcting the pipeend portion thereof to an angle of R≦0.5D or an angle corresponding tothis by using a first molding tool moved onto the pipe end portion;fitting a flange on the pipe end portion and expanding the pipe endportion projecting from the flange by using a second molding tool; andfixing the pipe end portion to the flange by pressing the expanded pipeportion against the flange by using a third molding tool.

The aforementioned “pure aluminum or aluminum alloy having softproperties” means a thermally refined O material or an H14 or H24material of JIS A1000 series, A3000 series, A5000 series, or A6000series, for example, a material of JIS A1100, A1N00, A3003, or A3203.The “aluminum having elongating properties though being hard” means amaterial having an elongation not lower than 15%, such as an A6063-T8material.

According to the present invention, the height of the horizontal portionof the L-shaped pipe could be made as small as possible by the selectionof the aforementioned material and by the performance of theaforementioned molding steps.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a side view of a conventional flange coupling;

FIG. 2 is a side view of a conventional flange coupling using anL-shaped pipe;

FIG. 3 is a partially broken side view of a flange coupling inaccordance with the present invention;

FIG. 4 is an end face view of a flange coupling in accordance with thepresent invention;

FIG. 5 is a plan view of a flange coupling in accordance with thepresent invention;

FIG. 6 is a bottom view of a flange coupling in accordance with thepresent invention;

FIGS. 7(A) to 7(E) are views showing a manufacturing process for theflange coupling shown in FIGS. 3 to 6;

FIG. 8 is a schematic view showing the state of an automotive airconditioner piping to which a flange coupling in accordance with thepresent invention is applied; and

FIG. 9 is a view showing a state in which a flange coupling inaccordance with the present invention is mounted to a compressor mount.

BEST MODE FOR CARRYING OUT THE INVENTION

FIGS. 3 to 6 show an embodiment of a flange coupling in accordance withthe present invention.

A flange 3 has an attaching bolt hole 1 and a pipe connection hole 2,and the pipe connection hole 2 has many vertical grooves 2′ formed inthe inside wall thereof. An L-shaped pipe 4 is fitted firmly in the pipeconnection hole 2 so as not to turn, and is fixed vertically by a sealboss portion 7. Reference numeral 8 denotes an O-ring groove.

The L-shaped pipe 4 is bent in a horizontal direction just from theupper surface of the flange 3 with a small radius of curvature R, and ahorizontal portion 5 thereof has a lower face 6 that is at almost thesame level as the upper surface of the flange 3.

FIG. 4 is a right end face view of FIG. 3, FIG. 5 is a plan viewthereof, and FIG. 6 is a bottom view thereof. In FIG. 6, an imaginaryline indicates that the angle of the pipe 4 with respect to the flange 3can be set freely, and also the flange 3 may be rectangular in the planview.

The above-described flange coupling is manufactured, for example,through steps shown in FIGS. 7(A) to 7(E).

First, a pipe material 10 specified as JIS A3003-O material (thermallyrefined O material of A3000 series) is used, and is formed into anL-shaped pipe with a radius of curvature that satisfies the condition ofR=0.6 to 0.9D (R: radius, D: pipe diameter) according to the usualpractice.

This pipe 10 is placed in a pipe clamp mold 11, and a first molding tool13 is lowered so as to cover a pipe end portion 12 of the pipe 10, bywhich the bend angle of the L-shaped pipe 10 is corrected to an angle ofR=0.5D or an angle corresponding to this.

The pipe clamp mold 11 is formed transversely with a hole 11 a. Thehorizontal portion 5 of the L-shaped pipe 10 is supported by the hole 11a, and the other end portion thereof is erected upward. A portion of thepipe clamp mold 11, which corresponds to the outside corner portion ofthe L-shaped pipe 10, is formed so as to fit the radius of curvature R1of the outside corner portion of the L-shaped pipe 10. Also, the firstmolding tool 13 is formed with an inside hole 13 a having an insidediameter that is approximately equal to the outside diameter of theL-shaped pipe 10. A portion at the opening of the inside hole 13 a,which corresponds to the inside corner portion 13 b of the L-shaped pipe10, is formed so as to fit the radius of curvature R2 of the insidecorner portion of the pipe 10. After the correction, the first moldingtool 13 is removed.

Next, a flange 14 is fitted on the pipe end portion 12, and a secondmolding tool 15 is lowered. The pipe 10 is pressed to the outside by alower end projecting portion 16 a of the second molding tool 15, bywhich the pipe end portion 12 is pressed against the grooves 2′ in thepipe connection hole 2 in the flange 14. Thereby, the pipe 10 is fixedin the pipe connection hole 2 so as not to turn. At the same time, thepipe end portion 12 is inserted in an expansion groove 17 in the secondmolding tool 15, by which the pipe end portion 12 is expanded.

The second molding tool 15 has a projecting portion 16 a with a diameterslightly larger than the inside diameter of the pipe 10 and a proximalend portion 16 b with a diameter larger than the inside diameter of thepipe 10. The projecting portion 16 a projects from a reference plane(contact face with the flange 14) of the second molding tool 15, and theexpansion groove 17 is formed around the proximal end portion 16 b.Also, a tapered portion 16 c in which the diameter decreases toward thedistal end is formed between the projecting portion 16 a and theproximal end portion 16 b. After the molding, the second molding tool 15is removed.

Next, a third molding tool 18 is lowered. Thereby, the pipe end portion12 is pressed against the flange 14 by a molding groove 19 and a stepportion 20, and thereby a pipe end portion 21 (the seal boss portion 7)with a diameter larger than the diameter of the horizontal portion 5 ofthe pipe is formed.

The third molding groove 19 has, like the second molding tool 15, aprojecting portion 25 a with a diameter equal to or slightly smallerthan the inside diameter of the pipe 10 and a proximal end portion 25 bwith a diameter larger than the inside diameter of the pipe 10. Theprojecting portion 25 a projects from a reference plane of the thirdmolding tool 18, and an expansion groove 26 is formed around theproximal end portion 25 b. Also, a step portion 26 a is provided at theboundary between the projecting portion 25 a and the proximal endportion 25 b, that is, in a position corresponding to the surface of theflange 14. This step portion 26 a is formed on the inside from thereference plane by the plate thickness of the pipe 10. A step is formedin the tapered portion of the pipe 10 by the step portion 26 a, and thisstep comes into contact with the surface of the flange 3.

Next, a groove 22 for fitting an O-ring is formed in the end portion 21of the pipe 10, thereby completing the product.

Although the first, second, and third molding tools are used in theabove-described embodiment, the molding shown in FIG. 7(C) can beperformed at a stroke using only the second molding tool 15 by omittingthe first molding tool 13. This is because the gist of the presentinvention is that an L-shaped pipe with a small radius of curvature R isformed, the L-shaped pipe is fixed non-rotatably to a flange, anexpanded portion is formed in the pipe end portion, an O-ring groove isformed therein, and a height h of a horizontal portion of the L-shapedpipe is made as small as possible.

Specifically, a pipe made of aluminum or aluminum alloy is bent into anL shape with a radius of curvature that satisfies the condition ofR≦1.0D (R: radius, D: pipe diameter), the L-shaped pipe is placed in thepipe clamp mold, the flange is fitted on the pipe end portion of thepipe, and the pipe end portion is expanded by the second molding tool15. Then, the bend angle of the L-shaped pipe is corrected to an angleof R≦0.5D or an angle corresponding to this by the flange 14, and theexpanded portion is pressed against the flange, by which the pipe endportion is fixed to the flange.

The above-described flange coupling is used, for example, as shown inFIG. 8.

In FIG. 8, reference character a denotes a condenser arranged in frontof a radiator, not shown, and b denotes a compressor connected to thecondenser a via a hose c. The compressor b is connected to a coolingunit e, not shown, via a hose d. Reference characters f, g and h denoteflange couplings installed at the ends of the hoses c and d, and theseflange couplings f, g and h are installed on a mount i provided on thecondenser a and mounts j, j provided on the compressor b. The presentinvention is applied to the above-described flange couplings.

FIG. 9 enlargedly shows a state in which the flange coupling g isinstalled on the mount j via an O-ring 24 by using a bolt 23.

According to the present invention, there can be provided a flangecoupling in which an L-shaped pipe is installed in a very low positionwith respect to a flange and a manufacturing method for the same. Whenthis flange coupling is used for automotive air conditioner piping, aspace near an engine can be utilized effectively, so that the quality ofautomobile design can be improved.

1. A manufacturing method for a flange coupling, comprising the stepsof: bending a pipe made of aluminum or aluminum alloy into an L shapewith a radius of curvature that satisfies the condition of R≦1.0 D (R:radius of pipe median line, D: pipe diameter), said aluminum or aluminumalloy being at least one kind selected from a group of pure aluminum oraluminum alloy having soft properties and aluminum having elongatingproperties through being hard; placing the resultant L-shaped pipe in apipe clamp mold and correcting the pipe end portion thereof to an angleof R≦0.5 D by pressing the vicinity of a pipe end portion with the useof a first molding tool which has a concave portion fitting the pipe endportion of said L-shaped pipe and has a lower end portion; fitting apipe connection hole of a flange provided with an attaching bolt holeand the pipe connection hole, on said pipe end portion, and pressingsaid pipe against the inside wall of said pipe connection hole andexpanding the pipe end portion projecting from said flange, with the useof a second molding tool which has a lower end portion with an outsidediameter slightly larger than the inside diameter of the said pipe andhas an expansion groove; and fitting said flange to the pipe end portionof the L-shaped pipe by pressing the expanded pipe end portion againstsaid flange with the use of a third molding tool which has a moldinggroove and a step portion.
 2. The manufacturing method for a flangecoupling according to claim 1, wherein said method comprising a step offorming a groove for fitting an O-ring in said pipe end portion, saidstep being performed after the step of fixing said pipe end portion tosaid flange.
 3. The manufacturing method for a flange coupling accordingto claim 1 or 2, wherein said aluminum or aluminum alloy is at least onekind selected from a group of pure aluminum or aluminum alloy havingsoft properties and aluminum having elongating properties though beinghard.